Poor interaction with threads (python 2.7)

添付された query.txt と、例に示されている GraphQLView.get_context エントリポイントから始め、続いて並行するリクエスト間で dummy_middleware、ネストされた resolver、promise.async_instance、Flask g を追跡します。提供されている Python 2.7 の例で失敗を再現し、実行がどこでスレッドを切り替えるのかを特定します。完了とは、相互作用を理解し、リクエストローカルなコンテキストを保持するための修正方針について合意できていることを意味します。

the interaction between this library, graphql-core, and promise appears to allow execution to hop threads especially (only?) when using a middleware and nested resolvers. this is inconsistent with flasks threading model and the ability to access the request/g thread locals

with the attached (very contrived) example, when submitting the query with concurrent requests the requests frequently fail because the key created in get_context doesn't exist on the threadlocal flask.g object in the resolvers. This happens when a thread accesses the promise.async_instance which isn't thread local, and resolves a promise that was created on a different thread.
query.txt

from flask import Flask
from flask_graphql import GraphQLView


app = Flask(__name__)

import graphene
import threading
import time
from flask import g

def get_user(info):
    return g.get(info.context['key']) 

class User(graphene.ObjectType):
    id = graphene.ID()
    name = graphene.String()
    friend = graphene.Field(lambda: User)
    age = graphene.Int()
    apple = graphene.String()

    @classmethod
    def resolve_friend(cls, root, info):
        time.sleep(.1)
        x = get_user(info)
        return User(id=id(root), name=':'.join([x.name, threading.current_thread().name]))
    
    @classmethod
    def resolve_age(cls, root, info):
        time.sleep(.1)
	return 5

    @classmethod
    def resolve_apple(cls, root, info):
        time.sleep(.1)
        return "Apple"

class Query(graphene.ObjectType):
    me = graphene.Field(User)

    def resolve_me(self, info):
        time.sleep(.1)
        return get_user(info)

schema = graphene.Schema(query=Query)

ahh = {}
def dummy_middleware(next, root, info, **args):
    return_value = next(root, info, **args)
    return return_value

import random
random.seed()

class TestQLView(GraphQLView):
    def get_context(self, request):
	# set a random key in g to be used by resolvers
        key = str(random.randint(0,50))
	name = threading.current_thread().name
        user = User(id=key, name=name)
        setattr(g, key, user)
	return {
	    'key': key
        }

app.add_url_rule('/graphql', view_func=TestQLView.as_view('graphql', schema=schema, graphiql=True, middleware=[dummy_middleware]))